export function debounce(func, wait, immediate) {
  let timeout, args, context, timestamp, result;

  const later = function() {
    // 据上一次触发时间间隔
    const last = +new Date() - timestamp;

    // 上次被包装函数被调用时间间隔last小于设定时间间隔wait
    if (last < wait && last > 0) {
      timeout = setTimeout(later, wait - last);
    } else {
      timeout = null;
      // 如果设定为immediate===true，因为开始边界已经调用过了此处无需调用
      if (!immediate) {
        result = func.apply(context, args);
        if (!timeout) context = args = null;
      }
    }
  };

  return function(...args) {
    context = this;
    timestamp = +new Date();
    const callNow = immediate && !timeout;
    // 如果延时不存在，重新设定延时
    if (!timeout) timeout = setTimeout(later, wait);
    if (callNow) {
      result = func.apply(context, args);
      context = args = null;
    }

    return result;
  };
}

export function DateManage(val) {
  let temp = val || 9;
  let time = new Date();
  let year = time.getFullYear(); // 获取完整的年份(4位,1970)
  let month = time.getMonth() + 1; // 获取月份(0-11,0代表1月,用的时候记得加上1)
  let date = time.getDate();
  let json = { start: "", end: "" };
  let preYear = Number(year) - Number(temp);
  let preDate = date;
  if (month === 2) {
    let d = new Date(preYear, month, 0);
    preDate = d.getDate();
  }
  json.start = preYear + "-" + month + "-" + preDate;
  json.end = year + "-" + month + "-" + date;
  return json;
}
